3.0 MODULAR SUPPORT SYSTEM 3.1.2 MT BEAM AND COLUMN LOAD TABLES
Beam Design Fundamentals
Support Conditions
Modular Support Systems Technical Guide , Edition 1
Hilti modular support system profiles may be used in a wide variety of beam applications . Beams are structural elements that resist applied loads perpendicular to their length .
Beams must be designed for shear , flexure ( bending ), torsion , and deflection . In some cases , beams may be subjected to an axial load that acts concurrently with the applied perpendicular loads , and the member must be accordingly designed for the combined effects of bending and compression . Examples of typical load , shear , and moment diagrams for beams are shown on page 31 . Per AISI S100-16 / CSA S136-16 , cold-formed steel beams , which typically consist of highly customized profiles with very slender elements , must be designed for the effects of local buckling , distortional buckling , and for yielding and global buckling . Additionally , local buckling interacting with yielding and global buckling must be checked . The load values given in the beam tables in this technical guide represent the controlling load capacities for beams that are sufficiently laterally braced with due consideration of these limit states . A fully braced beam is restrained against twisting about the beam ’ s longitudinal axis as well as lateral movement perpendicular to the beam ’ s longitudinal axis . For unbraced conditions , reductions must be applied to the allowable loads per page 49 .
Beam Loading
Beam load tables in this technical guide are based on a “ uniformly loaded " condition unless noted otherwise . Uniform loads are distributed evenly along the length of the member .
See page 32 for modification factors to be applied to allowable load values for non-uniform loading conditions .
A “ simply-supported " beam is a single-span beam , supported at its ends , whose supports restrain translation ( lateral movement ) in the 3 orthogonal directions as well as twisting about the beam ’ s longitudinal axis , but do not restrain bending moments .
A “ fixed-end " beam is a single-span beam , supported at its ends , whose supports restrain translation and rotation ( bending and twisting moments ) in the 3 orthogonal directions . Several Hilti MT connectors allow for moment resistance which can be used to simulate a “ fixed-end " beam .
A “ cantilevered " beam is a single-span beam , supported at only end and free to translate and rotate at its other ( unsupported ) end . The supported end of a “ cantilevered " beam is considered a “ fixed-end ". MT brackets are examples of “ cantilevered " beams .
Note that beam load tables in this technical guide are based on a “ simply-supported " beam span condition unless noted otherwise . See page 32 for modification factors to be applied to allowable load values for non-simply-supported span conditions .
Deflection
Beam designs can often be governed by deflection limits ( serviceability ). Beam deflections are computed based on the magnitude and type of applied loading , the member ’ s length , L , elastic modulus , E , moment of inertia about the axis under consideration , I , and support conditions .
Allowable loads corresponding to deflection limits in this technical guide are based on “ simply-supported " and “ uniformly loaded " conditions . See page 32 for modification factors to be applied to allowable load values for other conditions .
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